indigobush

Amorpha fruticosa

   

Family: Fabaceae

Other common names: False indigo, ibush, lead plant

Weed Class: B

Year Listed: 1988

Native to: Eastern and Central United States

Toxic: humans, livestock

Other Legal Listings: WA Quarantine list, WAC 16-750

additional photos

 

   

Why is it a noxious weed?

Although native to the Eastern United States, in some Western states it is considered invasive and has naturalized. It escapes planted areas and grows along streams and rivers and prairie draws forming dense thickets and outcompetes native species.

How would I identify it?

General Description: Indigobush is a thornless, deciduous, multiple stem shrub that can grow to over 12 feet tall and can form thickets.

Flower Description: Flowers are in dense, upright clusters, in the upper branches. They are blue-violet to dark purple and have 10 stamens.

Leaf Description: Leaves are made up of 13 - 25 leaflets which are one to two inches long. They are gland dotted and hairy with smooth margins.

Stem Description: Older stems are woody and younger stems are green and hairy.

Fruit/Seed Description: Seed pods are small, curved, dark brown, about 1/4 inch in size and are dotted with glands. Each pod contains 1 or 2 seeds.

May be confused with:

How does it reproduce?

Indigobush reproduces by seed.
 

Where does it grow?

Indigobush grows in prairies, hillsides, sandy roadsides, along streams and rivers. Please click here to see a county level distribution map of indigobush in Washington.
 

How do I control it?

Mechanical Control

Cutting plants may result in re-sprouting stems. Repeated cutting may be used to control seed production each year.

Herbicide Control

Please refer to the PNW Weed Management Handbook, or contact your county noxious weed coordinator.


 

For more information

 
See our Written Findings for more information about indigobush (Amorpha fruticosa).
See this detailed profile for more in depth information about indigobush (Amorpha fruticosa).
Report on Indigo bush from the book "Weed Control in Natural Areas in the Western United States"

Additional Photos


 
 

 


Indigobush in flower

 


Close up of compound leaf

 


Indigobush invasion along a creek

 


Indigobush growth

 


in flower

 


in flower

 


flowering plant

 


underside of leaflets

 


old fruits with glands

 


seed pods on dormant plant

 


dormant plant habit

    

back to page top